Boring machine



A. J. MGDONALD BORING MACHINE Filed Dec. 20, 1944 Oct. 15, 19.46. 1

2 Sheets-Sheet 1 INVENTOR. AunzswlM DoN m Oct. 15, 1946.'- A. J.McDQNALD- BORING MACHINE Filed Dec. 20, 1944 2 Sheets-Sheet 2 INVE1NTOR.ANDREW J1 MEDONAL-D ATTdENsi l atented Get. 15, 1946 UNITED STATESPATENT OFFICE BORING MACHINE Andrew Joseph McDonald, Philadelphia, Pa.Application December 20, 1944, Serial No. 568,946

3 Claims.

This invention relates to machine tools, more particularly to boringmachines of the horizontal hollow-bar type, and has for an object toprovide improved feeding means therefor.

In the horizontal hollow-bar type of boring machines now in general use,and in which a cutter head mounted on the hollow bar carries awork-engaging tool adapted to be fed radially of the bar through axialmovement of a pull-rodactuated wedge, the pull rod has a threaded endextending beyond an end of the hollow bar and threadedly engaged in aninternally-threaded gear nut. This gear nut is the last, or driven, gearof a-train of gears mounted on an end plate, carried by the end of thehollow bar, while the first, or driving, gear of the train includes aratchet wheel, or star, whose teeth, or points, engage a, kicker onceduring each revolution of the hollow bar to drive the gear train androtate the gear nut to move the pull rod axially.

Inasmuch as the end of the hollow banon which the star and its train ofgears are mounted, usually projects several feet beyond the spaced pairof pedestals which support the bar, it has been customary to provide athird pedestal, adapted to carry the kicker and to be placed, by theoperator, in a position where the kicker will engage the points of thestar as the bar rotates. Inasmuch as the bar is usually some four and ahalf or live feet above the floor, the third pedestal has to be of acorresponding height, and consequently of considerable width to preventits being'upset. As a result, such pedestals usually weigh severalhundred pounds, and such weight is further desirable to preventaccidental movement of the pedestal, which could easily occur if thepedestal were not very heavy, particularly as such machines are usuallyarranged at right angles to an aisle in the machine shop, with the endof the bar carrying the star adjacent the aisle and sometimes evenprojecting into the latter which means that the third pedestal also mustbe in or near the aisle, where it is subject to knocks by passingtrucks, cranes, etc. Obviously, such accidental movement of the pedestalwould. interrupt radial feed of the tool if the kicker were moved outofthe pathjof the star, and would cause too rapid feed, or even breakage,if the kicker were moved so as to engage too many of the star teeth ateach contact therewith.

'Another serious disadvantage of the use of the third. pedestal to carrythe kicker is that, when the hollow bar is moved axially to align thetool with a different part of the work to be machined, the'thirdpedestal and its kicker must also. be

moved to maintain cooperation of the kicker with the star. In many typesof boring, for example, in cutting the radial grooves in turbinecylinders or casings for reception of turbine blade roots, the bar hasto be moved axially to several dozen difierent positions, each requiringa new positionof the heavy pedestal carrying the kicker.

Therefore, another object of the present invention is to provide a fixedsupport for the kicker of a horizontal hollow-bar boring machine feedmechanism.

A further object of the invention is to provide, in a boring machine ofthe horizontal hollow-bar type, a tool-feeding mechanism having a fixedposition for the kicker and star, together with a flexible drive fromthe star to the work-engaging tool.

Another object of the invention is to provide, in a boring machine ofthe horizontal hollow-bar type, a star clamp ring adapted to be securedto the horizontal bar adjacent one of the bar-supporting pedestals,together with a star rotatably supported by the clamp ring, and a shaftof noncircular cross section rotatable with the star and having aslidable driving connection with the conventional feed mechanism of suchboring machines.

Yet another object of the invention is to'provide a fixed support forthe kicker of a boring machine radial feed mechanism.

A further object of the invention is to provide, in the radial feedmechanism of a boring machine, a star and kicker therefor, both having afixed position axially of the machine, together with means for providingcontinuous feeding drive from the star to the radially-fed tool,regardless of the axial position of the boring bar relative to the starand its kicker.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in accordancewith the accompanying drawings, forming a part of this application, inwhich:

Fig. 1 is a side elevational view of a horizontal hollow-bar type ofboring machine embodying the principles of the present invention;

Fig. 2 is an enlarged perspective view of the kicker mechanism;

Fig. 3 is an. enlarged, fragmentary elevational view of the right-handend of the structure illustrated in Fig. 1;

Fig. 4 is an enlarged, fragmentary sectional view of the work-engagingtool and its feeding mechanism, taken along the line IV-IV of Fig.

3, looking in the direction indicated by the arrows;

Fig. is a sectional View, taken along the line V-V of Fig. 4, looking inthe direction indicated by the arrows; and,

Fig. 6 is a sectional View, taken along the line VI-VI of Fig. 4,looking in the direction indicated by the arrows.

Referring now to the drawings more in detail, and particularly to Fig. 1thereof, the reference character It! indicates, in its entirety, aboring machine of the horizontal, hollow-bar type and comprising a pairof spaced pedestals II and I2, bolted, or otherwise secured, to theusual bedplate I3. The pedestals carry bearings (not shown), in which isjournaled the horizontally-disposed hollow bar 4. The pedestal It, andits extension Ila, house the gearing and control mechanism through whichthe bar It is rotated by a motor (not shown), the main gear being withinthe gear casing Hi.

The bar I4 is provided with an axial bore ll, Fig. 4, extending entirelytherethrough, and a plurality of axially-spaced radial openings I8provide for radial feed of the Work-engaging tool IS, in the mannerhereinafter described. The cutter head 2|, formed in two parts 22 and23, clamped on the bar it by bolts M in the mating flanges 26 and .21,is provided with a radial groove 28,, in which a tool carrier 29 isslidably retained by the plate 3!. A feed push pin 32 extends radiallythrough a selected one of the openings 18 of the bar and transmitsradial movement to the tool carrier 29 from an axially-movable cammember or wedge 33, disposed in the bore I! of the bar Id. The wedge 33has an inclined surface 34 at the bottom of a groove 35, mating with acorrespondingly-inclined surface 36 on the inner end of the feed pushpin 32, which inner end is slidably received in the groove 35 of thewedge 33.

A pull rod 3'! is threadedly connected to the wedge member 33, at andhas its other end threadedly received in the pull rod nut 39, beyond therighthand end of the hollow bar 14, as viewed in Figs. 1 and 4. The nut39 is non rotatably received in a mating recess 4|, in a driven gear 42,whose hollow extension shaft 63 is rotatably mounted in a bearingopening 44 in the end plate M5.

A collar 40 surrounds a portion of the pull rod nut 39 and retains it inthe recess 4|, the collar 40 being held by the set screws 45. The endplate 4% is fixedly secured on the end of the hollow bar l4 and carriesa driving gear 4?, and a pair of intermediate or idler gears 48 and 45,mounted on stub shafts 5| and 52, respectively. A third stub shaft 553is provided, and the idler gear 48 may be removed from the stub shaft 5|and placed on'the shaft 53 to obtain rotation of the driven gear 4-2 inthe same direction, regardless of the direction of rotation of the barM, as a result of establishing a four-gear train in place of thethree-gear train illustrated in Fig. 3.

The end plate 46 is provided with a bear-ing opening 54 rotatablyreceiving the hollow extension shaft ES of the driving gear Q'L'thisgear having an axial opening 51 therethrough of square cross section forreception of the rod or shaft 58 of corresponding cross section.Obviously, the opening 51 and shaft 58 may be of any non-circularsection.

Inasmuch as the shaft 58 and the axial opening 57 of the gear 47, inwhich the shaft is received, are of the same shape and have a slidingfit, rotation of the shaft will effect corresponding rotation of thedriving gear 41, and hence of the entire gear train, including the pullrod nut 39.

Since the bar l4 and its end plate 46 and driving gear 4! are adapted toslide longitudinally relative to the shaft 58, the gear 41 is retainedin position against the end plate by suitable means, such as the anglepiece 59, secured to the end plate by the screws 6|, and overlapping theouter face of the gear 47, with the shaft 58 extending through theopening 62 in the angle piece.

A star clamp ring 63, in the form of a split collar 64, having a joint66 provided by the mating flanges 61 and 68, which are adapted to bedrawn together by bolts 69, is clamped on the hollow bar l4 adjacent theouter bushing H of the pedestal l2. The star clamp ring 63 may, inaddition to or in place of being clamped, be bolted to the bushing 7| bybolts extending through the openings 72 in the clamp ring (Fig. 6).

The upper flange 68 of the star clamp ring extends slightly more thandegrees about the ring and includes a portion 73 of maximum radialextent, in which is provided a bearing opening 14, rotatably supportinga stub shaft 16. The stub shaft is retained in position in the hearingopening 14 by the flange T! at one side and by by the star or ratchetwheel 78, on the shaft extension 19, at the other side. The star I8 iskeyed to the shaft extension 79, as at 8 I, and is retained thereon bythe set screw 82.

The flange H is provided with an axial opening 83, of square crosssection, to receive the terminal portion 84 of the square shaft 58, theterminal portion being retained therein by the set screw 86.

A kicker indicated in its entirety by the reference 81, Figs. 2 and 3,is mounted on the outer face of the pedestal l2, and comprises a block88 having a groove 89 extending lengthwise thereof. A kicker tongue 9|is slidably retained in the groove 89 by the guide straps 92, and may beadjusted therealong by the screw 93, threadedly mounted in the end strip94, with its inner end rotatably secured to the rear end of the tongueand its outer end provided with a finger piece 96. The tongue may befurther secured in any selected position of adjustment by tightening ofthe clamping stud 91, which is threadedly mounted in the tongue, so thatthe point of the stud engages the bottom of the groove 89. The screws93, which retain the guide straps 92 on the block 88, may be ofsufficient length to also secure the complete kicker assembly 81 to thepedestal I2.

The hollow bar M is provided with an external keyway 99 extending fromend to end thereof and receiving keys |0|, I02 and H13, cooperating withradially-aligned keyways in the star clamp ring 63, the end plate 46,and the cutter head 2|, respectively. The keyways in the star clamp ringand in the end plate are so disposed that the bearing openings 14 of theformer and 54 of the latter, are axially aligned, with the result thatthe shaft 58 is parallel to the bar M at all times.

In operation, the apparatus is arranged as previously described and asillustrated in the drawings, particularly Fig. 1, wherein the cutterhead 2| is shown positioned with its tool I!) engaging a surface of thework which requires a radial cut. The dot-dash lines of Fig. 1 indicatethe longitudinal cross section of a turbine lower casing, comprising thework W. The driving mechanism, housed within the pedestal II and itsextension Ila, rotates the hollow bar [4, together with the cutter headIS, the bushing 1|, the star clamp ring 63, the end plate 46 and itstrain of gears 41, 48 and 122. During each complete revolution of thebar Hi, one of the points 80 of the star 18 is engaged, by the tongue 91of the kicker 87. Where a ten point star is used, as herein illustrated,the squared shaft 58 will be rotated one-tenth of a complete turn, andsuch rotation of the shaft 58 actuates the gear train to correspondinglyrotate the pull rod nut 39. As this nut turns, the pull rod 31, which isnon-rotatable relative to the bar l4 and end plate 46, is moved axiallyof the bar [4, imparting the same axial movement to the wedge member 33,thereby moving the feed push pin 32 and its associated tool carrier 29and tool l9, radially.

When machining of one radial groove of the work W has been completed, itis only necessary to loosen the bushing H and the star clamp ring 63 onthe bar M and to move the latter axially, to bring the tool [5 intoposition at the new groove of the work, after which the bushing 1| andstar clamp ring are again tightened on the bar 14, and the machiningoperation repeated. When the bar I4 is thus moved to bring the tool toits new position, the driving gear 41 merely slides along the squaredshaft 58, without any change in the alignment of the star 18 and thekicker 81. Thus the previously necessary moving of a third pedestal,carrying the kicker, to align the latter with the new position of thestar, where the latter was mounted on the end plate and therefore movedwith the star, is entirely eliminated by the present invention.

While this invention has been illustrated in but one form, it will beapparent to those skilled in the art that it is not so limited, but issusceptible of various changes and modifications, without departing fromthe spirit thereof.

What is claimed is:

1. Apparatus of the character described comprising a pair of spacedpedestals, a hollow bar rotatably and slidably supported in horizontalposition by said pedestals, a cutter head secured on said bar andincluding a radially-movable cutting tool, a wedge axially movable inthe bore of the hollow bar and adapted when so moved to move the cuttingtool radially, an end plate secured to one terminal portion of thebar,-a rod secured at one end to the wedge and having its other endexternally threaded and extending through and beyond said end plate, atrain of meshing gears mounted on said end plate and including a driving gear having an axial bore and a driven gear having a threaded borethreadedly receiving the threaded end of the rod, a star-supporting ringsecured On the bar adjacent the pedestal nearest the end plate andhaving a bore therein axially aligned with the bore of the driving gear,a shaft mounted in said axially-aligned bores, a star fixedly secured onsaid shaft, and a kicker mounted on the last-mentioned pedestal for en-6 gaging and rotating the star responsive to rotation of the bar, theshaft being rotatably and nonslidably mounted in the, bore of thestar-supportingv ring and being slidably and non-rotatably mounted inthe bore of the driving gear, whereby rotation of th star upon contactthereof with the kicker will actuate the wedge-moving rod regardless ofaxial adjustments of the hollow bar relative to the pedestal-supportedkicker.

2. Apparatus of the character described comprising a pair of spacedpedestals, bearings carried by said pedestals, a hollow bar rotatahlyjournaled in said bearings in horizontal position and axially adjustablerelative thereto, a cutter head secured on said bar and including aradially-movable cutting tool, a wedge axially movable in the bore ofthe hollow bar and adapted when so moved to move the cutting toolradially, a pull rodwithin the bore of the bar and secured at one end tothe wedge with its other end threaded and projecting beyond an end ofthe bar, a train of gears carried by said bar adjacent said end thereofand including a driving gear having an axial bore and a driven gearhaving a threaded bore threadedly receiving the threaded projecting endof the pull rod, a star-supporting ring secured on the bar inpredetermined position axially thereof relative to the pedestals andhaving a bore therein axially aligned with the bore of the driving gear,a shaft mounted in said axially-aligned bores, a star secured on saidshaft, and a kicker supported by one of the pedestals in position toengage and rotate said star responsive to rotation of the bar, saidshaft being rotatably and non-slidably mounted in the bore of thestar-supporting ring and being slidably and non-rotatably mounted in thebore of the driving gear, whereby rotation of the star upon contact withthe kicker will actuate the wedge-moving pull rod regardless of axialadjustments of the hollow bar relative to the pedestal-supported kicker.

3. In mechanism for feeding radially the cutter of a horizontalhollow-bar type of boring machine, wherein a train of gears effectsaxial movement of a pu1l-rod-actuated cutter-feeding wedge; a stationarysupport; a kicker carried by said stationary support; a movable support;a shaft carried by said movable support and adapted to rotate relativethereto; a star carried by said shaft and adapted to rotate the latterrelative to the movable support; means for imparting motion to themovable support, the kicker being. so positioned with respect to themovable support and the shaft and star carried thereby that said star iscontacted and partially rotated b the kicker during each cycle ofmovement of said movable support; and an axially-slidable drivingconnection between the shaft and the train of gears, whereby the partialrotation of the star due to contact thereof with the kicker istransmitted through the shaft to the gear train, said sliding connectionproviding for transmission of rotation from the star to the gear trainregardless of the axial spacing of said star and gear train.

ANDREW JOSEPH MCDONALD.

